A speaker has a voice coil and a diaphragm interposed between magnets and generates a sound as the diaphragm vibrates by the movement of the voice coil.
A plate type speaker has a plate voice coil and magnets arranged at both sides of the voice coil with a predetermined space, and an induced electromotive force is generated by the Fleming's left hand rule and the Lorentz rule to form a frequency corresponding to a voice and reproduce the sound by vibrating the diaphragm using the frequency.
The voice coil is spirally wound or printed as a pattern in an oval shape on one side or both sides of a coil base of a plate shape so as to form a voice coil plate.
The diaphragm is attached on the top of the voice coil plate in the lengthwise direction, and a sound is generated as the diaphragm vibrates according to the movement of the voice coil plate.
A guide damper is used to transfer the vibration from the voice coil plate to the diaphragm, and a damper covered with a piece of thin cloth or made of a metal material is used as the guide damper in the prior art.
In the plate type speaker, although the structure of the voice coil is important to efficiently transfer sound energies, damper capability of the guide damper, which is a medium for transferring the energies, is very important. For this reason, development of the guide damper is still under progress and advanced until present.